5.56 Ammo, How To ID Bullet Weight?
Without busting it down and weighing a bullet, that is.
My issued M16A1 was made in 1975, and has the older 1:9 (I think) twist barrel. It shoots well with the issued 55 grain .223 Remington ammo.
I have on hand a quantity of GI 5.56 ammo and I don't know what the bullet weight is. I am hoping one of you can tell me from the available markings whether this is 55 grain or 62 grain ammo.
Headstamp is L C 8 1. I presume that means Lake City Arsenal, made in 1981.
The ammo is not in boxes, but on bandoliers, and the bandolier is marked, "BALL M193" and "LC-81K001-186."
I called my rifle guy and he said, "Just shoot it, and if it shoots OK, it is right for the rifle."
I would sorta like to know. If it is 55 grain, I will shoot it. If it is heavier, I may try to swap it for some of the same with the lighter bullets.
Thanks.
My issued M16A1 was made in 1975, and has the older 1:9 (I think) twist barrel. It shoots well with the issued 55 grain .223 Remington ammo.
I have on hand a quantity of GI 5.56 ammo and I don't know what the bullet weight is. I am hoping one of you can tell me from the available markings whether this is 55 grain or 62 grain ammo.
Headstamp is L C 8 1. I presume that means Lake City Arsenal, made in 1981.
The ammo is not in boxes, but on bandoliers, and the bandolier is marked, "BALL M193" and "LC-81K001-186."
I called my rifle guy and he said, "Just shoot it, and if it shoots OK, it is right for the rifle."
I would sorta like to know. If it is 55 grain, I will shoot it. If it is heavier, I may try to swap it for some of the same with the lighter bullets.
Thanks.
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Well, I THINK that all of the new 62 grain stuff has a green tip. At least, all of it I've seen does...
Hope this helps.0 -
M193 is 55 grain.
a 1 in 9 twist will shoot 55 and 62 equally well.0 -
quote:Originally posted by nunn
Without busting it down and weighing a bullet, that is.
My issued M16A1 was made in 1975, and has the older 1:9 (I think) twist barrel. It shoots well with the issued 55 grain .223 Remington ammo.
I have on hand a quantity of GI 5.56 ammo and I don't know what the bullet weight is. I am hoping one of you can tell me from the available markings whether this is 55 grain or 62 grain ammo.
Headstamp is L C 8 1. I presume that means Lake City Arsenal, made in 1981.
The ammo is not in boxes, but on bandoliers, and the bandolier is marked, "BALL M193" and "LC-81K001-186."
I called my rifle guy and he said, "Just shoot it, and if it shoots OK, it is right for the rifle."
I would sorta like to know. If it is 55 grain, I will shoot it. If it is heavier, I may try to swap it for some of the same with the lighter bullets.
Thanks.
The older M16A1s had a 1-12 twist. Some were upgraded to a 1-7 twist in order to fire the heavier, 63gr bullets as opposed to the 55gr bullets (M193).
BTW, here is a website that will PROBABLY answer all your ballistics questions concerning the M16A1 and the the M193 bullets
http://www.usarc.army.mil/417TransDet/appf.htm0 -
Thanks. 1:12 twist. See? I told you I was ignorant. Seems that the M193 ammo will work OK in the A1, so I will use it. 0 -
quote:Originally posted by nunn
Thanks. 1:12 twist. See? I told you I was ignorant. Seems that the M193 ammo will work OK in the A1, so I will use it.
Yep, that's what it's designed for. That link should help out with some your sight adjustment too, you can go through the whole manual I believe.0 -
We got the sights dead on when we zeroed the rifles and qualified. I am very confident in my ability to hit with it up to about 200 yards using the issue ammo. Fortunately, this rifle has the old-style sights, too, so once it is zeroed, it should stay zeroed. 0 -
Don't underestimate how good that old gun will shoot. Any higher twist rate and the bullets will keyhole on out past 200yd. That is exactly why the 1-14 twist rates were put aside. Bullets unstablize and tumble. Shooting off the bench and shooting freehand is a whole different ballgame. Just keep shooting it and working on the hard trigger pull most them guns have. Once mastered the gun should do 200 yd. groups that would make varmits history. 0 -
yep, what rogue_rob said. it's my understanding that military barrels will be either 1/12 or 1/7, the 1/9 was conjured up by mfrs for the civilian market to comprimise between all weights of bullets.
so, being an older M16, it's gotta be a 1/12.
if you want to be sure, just run the cleaning rod down the barrel and see how far it takes to make it turn 1 revolution. it's easy to tell, either 7, 9, or 12 inches.
aaaand, I tried shooting 55 gr. from a 1/7 barrel. accuracy was crap, you'd know it.0 -
quote:Originally posted by buschmaster
yep, what rogue_rob said. it's my understanding that military barrels will be either 1/12 or 1/7, the 1/9 was conjured up by mfrs for the civilian market to comprimise between all weights of bullets.
so, being an older M16, it's gotta be a 1/12.
if you want to be sure, just run the cleaning rod down the barrel and see how far it takes to make it turn 1 revolution. it's easy to tell, either 7, 9, or 12 inches.
aaaand, I tried shooting 55 gr. from a 1/7 barrel. accuracy was crap, you'd know it.
Help out an idiot.
So, the heavier bullet is used with less barrel twist? The 1/9 is a compromise that shoots either one just as good or poorly?0 -
Heavier bullet=more(faster) twist-- 1:7 works with the heavier (>70) grain .223 bullets; the 1:12, 1:14 twists work better with the lighter (<50 grn) bullets.
I've found that the 1:9 twist works pretty well with everything from 55 to 69 grains, with the 62-69 grain range performing the best.0 -
Your rifle has a 1/12 barrel, which is designed to fire 55gr. M193 ammunition. If you pick up an AR/M16 rifle and are unsure, their barrels are generally stamped with the twist rate just forward of the front sight assembly. If you see an AR-type with no twist rate marking it's probably a 1/12 made before there was really a need to specify. Those "C MP" markings on your M16A1 barrel indicate the bore and chamber are chromed and the barrel has been magnetic particle tested.
The newer 62gr. M855 ammunition (NATO designation SS109) that's designed for the newer model's 1/7 barrel can be identified by it's light green tip. When held alongside an M193 round you can also see that the bullet has a slightly different profile.
M193 can be fired through a 1/7 barrel but will give larger groups. Within about 100-150 yds. it's not too bad for defensive purposes, actually grouping about like the average 7.62x39 AK.
M855 shoots very poorly out of a 1/12 barrel, along the lines of 15 in. at 100 yds. In other words, it will function through the rifle just fine but should only be used in dire emergency short range situations.
As for wounding capacity with ball ammunition, you have the best rifle of the M16 series. M193 out of a 20in. 1/12 barrel performs exceptionally well against soft targets between about 85-150 yds. At these distances it's velocity is in the magic window where the bullet keyholes rapidly (~5in.), breaks at the cannelure and fragments heavily. Pop any animal at these ranges that will allow you 7 in. or so of penetration and you'll see the impressive results I'm referring to.0 -
I don't know, dude. I shot a possum with the M16 tonight and it ran off. I found it later, bleeding from a chest wound and eating the cat food, and did it in properly with a 12 gauge. 0 -
quote:Originally posted by nunn
I don't know, dude. I shot a possum with the M16 tonight and it ran off. I found it later, bleeding from a chest wound and eating the cat food, and did it in properly with a 12 gauge.
Bullet go right through it?0 -
In and out, minimial tissue damage and little blood loss. And that was one of those highly-touted high performance rounds. I forget who made them. 0 -
Not the hollow kind then? 0 -
that was the problem they had with the high performance ammo they were using(might still be for all i know) in mogadishu. the somaliansthey were shooting at were all hopped up on khat and the rounds went through and through casuing little or no damage. needed several well placed rds tobe effective. 0 -
that's because it's meant for gophers, not possums! you need the 69 gr. with the 1/7 twist barrel for possums. 0 -
Might as well use .22LR 0 -
quote:Originally posted by Captplaid
Help me out....
So, the heavier bullet is used with less barrel twist? The 1/9 is a compromise that shoots either one just as good or poorly?
(p64mak got it)0 -
hey, uhh, nunn, if you're going to be in charge of care and feeding of that sucker, you oughta get a manual on how much & where to lubricate it correctly. 0 -
I think you have a 1 in 9 twist.
The 1 in 12 twist barrel gave our guys in Nam a lot of problems in the the mid to late 60's and was switched over to 1 in 9.0 -
quote:Originally posted by RugerNiner
The 1 in 12 twist barrel gave our guys in Nam a lot of problems in the the mid to late 60's and was switched over to 1 in 9.
Colt has never used 1/9. All M16 and M16A1 rifles were 1/12. In the 80's Colt began 1/7 rifling (M16A2) to accomodate the heavier M855 bullet. Several other AR-type manufacturers began using 1/9 after this time in order to allow use of either round.
The only barrel changes Colt made to rectify problems of the early M16/M16A1 rifles was to chrome the bore and chamber. This became effective in early '67.0
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